From 4b04589b097896795648de38b1e9bbc7570d9696 Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Mon, 1 Aug 2022 17:12:21 -0500 Subject: Add support for CONFIGURE_POSIX_TIMERS_FACE_BEHAVIOR This adds the configure option CONFIGURE_POSIX_TIMERS_FACE_BEHAVIOR which allows the application to choose whether to have the POSIX timer_create() function follow the behavior defined by POSIX or the FACE Technical Standard. Updates #4691. --- cpukit/include/rtems/confdefs.h | 1 + cpukit/include/rtems/confdefs/face.h | 81 ++++++++++++++++++++++++++++++++++++ cpukit/include/rtems/posix/timer.h | 18 ++++++++ cpukit/posix/src/psxtimercreate.c | 31 +++++++++++++- 4 files changed, 129 insertions(+), 2 deletions(-) create mode 100644 cpukit/include/rtems/confdefs/face.h (limited to 'cpukit') diff --git a/cpukit/include/rtems/confdefs.h b/cpukit/include/rtems/confdefs.h index e6dd3d70ee..3927d26ec5 100644 --- a/cpukit/include/rtems/confdefs.h +++ b/cpukit/include/rtems/confdefs.h @@ -64,6 +64,7 @@ #include #include #include +#include #include #include #include diff --git a/cpukit/include/rtems/confdefs/face.h b/cpukit/include/rtems/confdefs/face.h new file mode 100644 index 0000000000..25f321108c --- /dev/null +++ b/cpukit/include/rtems/confdefs/face.h @@ -0,0 +1,81 @@ +/* SPDX-License-Identifier: BSD-2-Clause */ + +/** + * @file + * + * @ingroup RTEMSImplApplConfig + * + * @brief This header file evaluates configuration options related to + * the FACE Technical Standard. + * + * The FACE Technical Standard (https://opengroup.org/face) is an + * open standard designed for safety critical embedded systems. It + * includes POSIX profiles and requirements that promote safety + * and portability. As a general rules, the profiles place a minimum + * on the services which an operating system must provide. Those + * same profile definitions represent the maximum services which + * an application may use. + */ + +/* + * Copyright (C) 2022 On-Line Applications Research Corporation (OAR) + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _RTEMS_CONFDEFS_FACE_H +#define _RTEMS_CONFDEFS_FACE_H + +#ifndef __CONFIGURATION_TEMPLATE_h +#error "Do not include this file directly, use instead" +#endif + +#ifdef CONFIGURE_INIT + +#include + +#ifdef CONFIGURE_POSIX_TIMERS_FACE_BEHAVIOR + int _POSIX_Timer_Is_allowed( + clockid_t clock_id + ) + { + /* + * Per the FACE Technical Standard, POSIX timers should not be + * allowed on CLOCK_REALTIME for safety reasons. If the application + * wants the FACE behavior, then this method is instantiated. + */ + if ( clock_id == CLOCK_REALTIME ) { + return EPERM; + } + + if ( clock_id != CLOCK_MONOTONIC ) { + return EINVAL; + } + + return 0; + } + +#endif /* CONFIGURE_POSIX_TIMERS_FACE_BEHAVIOR */ + +#endif /* CONFIGURE_INIT */ + +#endif /* _RTEMS_CONFDEFS_FACE_H */ diff --git a/cpukit/include/rtems/posix/timer.h b/cpukit/include/rtems/posix/timer.h index 05a6f36eab..86b45ba05d 100644 --- a/cpukit/include/rtems/posix/timer.h +++ b/cpukit/include/rtems/posix/timer.h @@ -94,6 +94,24 @@ extern Objects_Information _POSIX_Timer_Information; NULL \ ) +/** + * @brief Follow POSIX or FACE Technical Standard on timer_create + * + * POSIX allows for the creation of timers based on CLOCK_REALTIME. + * This is viewed as a safety issue by the FACE Technical Standard + * and required to return an error. These are conflicting behaviors. + * This method is instanced by configuration when FACE conformant + * behavior is desired by the application. + * + * @param[in] clock_id is the clock ID to validate + * + * @return 0 if @a clock_id is allowed for use. Otherwise an errno value. + */ +int _POSIX_Timer_Is_allowed( + clockid_t clock_id +); + + /** @} */ #ifdef __cplusplus diff --git a/cpukit/posix/src/psxtimercreate.c b/cpukit/posix/src/psxtimercreate.c index 0eefac3f42..907da01836 100644 --- a/cpukit/posix/src/psxtimercreate.c +++ b/cpukit/posix/src/psxtimercreate.c @@ -51,6 +51,31 @@ #include #include +RTEMS_WEAK int _POSIX_Timer_Is_allowed( + clockid_t clock_id +) +{ + int rc = 0; + + /* + * Allow timer_create(CLOCK_REALTIME. ...) per POSIX by default + * on CLOCK_REALTIME or CLOCK_MONOTONIC. + * + * But per the FACE Technical Standard, POSIX timers should not be + * allowed on CLOCK_REALTIME for safety reasons. If the application + * configures that it wants the FACE behavior, then this method + * is overridden by . + */ + + if ( clock_id != CLOCK_REALTIME ) { + if ( clock_id != CLOCK_MONOTONIC ) { + rc = EINVAL; + } + } + + return rc; +} + int timer_create( clockid_t clock_id, struct sigevent *__restrict evp, @@ -58,9 +83,11 @@ int timer_create( ) { POSIX_Timer_Control *ptimer; + int rc; - if ( clock_id != CLOCK_REALTIME && clock_id != CLOCK_MONOTONIC ) - rtems_set_errno_and_return_minus_one( EINVAL ); + rc = _POSIX_Timer_Is_allowed( clock_id ); + if ( rc != 0 ) + rtems_set_errno_and_return_minus_one( rc ); if ( !timerid ) rtems_set_errno_and_return_minus_one( EINVAL ); -- cgit v1.2.3